Tractor



A. MAZZOLA Oct. 20, 1953 TRACTOR 2 Sheets-Sheet l Filed July 16, 1949 /N VEA/Tof? ,QN/@Rosa MAZZOLA Patented Oct. 20, 1953 UNITED STATES PATENT OFFICE TRACTOR Application July 16, 1949, Serial No. 105,193

7 Claims.

This invention relates generally to tractors adapted for movement along a track and capable of pulling and pushing carriers along said track, and more particularly to a tractor which is travelable along an overhead monorail and adapted to move cranes and other tramrail equipment therealong.

One object of the invention is to provide a tractor of the character referred to which is especially simple in construction and highly efiicient in operation.

Another object is to provide a tractor of this type which includes resilient tractor wheel means engageable with the monorail, an electric motor, a iiuid coupling operated by the motor, and driving means between the coupling and said traction wheel means for rotating the latter. By this arrangement, a powerful, efficient tractor unit is provided and smooth, quiet operation is assured.

Another important object is to provide a tramrail tractor unit which has a one piece housing for enclosing the operating elements, thus greatly simplifying the structure and minimizing the manufacturing cost of the unit. A related object is to provide a novel means for mounting the operating elements within the one piece housing in a manner such that the electric driving motor, the fluid coupling and associated parts can oe readily installed within and removed from the housing as a unit. By this provision, these parts can be assembled in a subassembly operation and thereafter installed in the housing, the subassembly being easily removed for inspection and servicing. Moreover, this arrangement of parts results in a compact, self contained unit which is considerably smaller than prior monorail tractors of this general character.

Another object is to provide a novel and unique means for assembling and mounting an electric driving motor in a one piece housing, said means including a cup-shaped holder or casing having a bearing in its end wall, the stator of the motor being receivable in the casing and keyed against rotation therein, and the rotor of the motor being carried by a shaft rotatable in the bearing and projecting therefrom to serve as a drive shaft, said shaft having an enlarged portion adjacent its rotor supporting end and abutting one side of the bearing, and a split ring engageable in a peripheral groove of the shaft and disposed against the other side of the bearing, said enlarged portion and said ring together retaining the rotor and its shaft in position and taking the axial thrust in both directions. By this construction, the components of the electric motor can be quickly assembled in and removed from the holder or casing and this makes for economy of manufacture and greatly facilitates servicing the power unit. Moreover, by this construction it is possible to utilize stators and rotors of various sizes to readily obtain a motor having the required power and characteristics. In accordance with the invention, the cup-shaped motor casing has a peripheral flange capable of being readily secured to a partition within the main housing of the tractor so that the entire motor assembly can be quickly installed and removed.

Another object of the invention is toprovide traction wheels for mounting the tractor for movement along an overhead monorail, the tractor having a single wheel preferably, although not necessarily, provided with a resilient tire engageable against the lower side of the monorail, and a pair of wheels engageable against the upper side of the rail or track. A related object is to provide means for adjusting the upper wheels toward and away from the lower wheel so as to obtain the gripping action necessary to cause the tractor to move along the track when the lower wheel is rotated. By this adjusting means, the position of the upper Wheels can be varied for the purpose of leveling the tractor, particularly in a plane normal to the monorail. As a further object and feature of the present invention, the upper wheels are rotatable at the ends of arms pivoted to the housing, the arms being so mounted that they can be readily removed and replaced byother arms of different widths so as to space the upper wheels in accordance with monorails of different sizes.

Further objects of the invention will become apparent from the following description of the tractor and from the drawings, which are for the purpose of illustration only, and in which:

Fig. 1 is a front elevational view of my -irnproved tractor, showing it arranged to travel along a monorail;

Fig. 2 is an enlarged longitudinal sectional View of the tractor;

Fig. 3 is an enlarged cross-sectional view, taken on line 3-3 of Fig. l;

Fig. 4 is a vertical sectional view, taken on line `4ll of Fig. 3;

Fig. 5 is a sectional view, taken on line 5 5 of Fig. 2; and

Fig. 6 is a sectional view, taken yon line 6-6 of Fig. 2.

Referring to the drawings in detail, my improved tractor l is designed for the purpose of traveling along a track I I which may be a mono- 'arate tire.

provided with a circular opening 2I in its lower portion. A horizontal wall 22 extends between the partition 29 and the end wall I9. By this construction, the partition 29. andthe horizontal wall 22 divide the housing I5 into a'forward compartment 23, a rearward compartment 24 and aV wall-like compartment 25 having an open upper end and provided with end walls. 26 and 21 (Fig. 3). The open forward end of the housing I5 is normally closed by a dish-shaped cover 35 which is secured tothe housing by screws 3i. Fastened against the end wall t9 of the housing by screws 32 is a similar cover 33 which denes, with said end wall, a casing for enclosing driving means, to be later described. At its upper end, the hous ing I has a pair of vertically spaced, horizontal ears 35'adjacent eachend, pins 35 and 31 extending between the ears providing means by which the tractor can be coupled to any tramrail unit which it is desired to pull or push along the monorail II. The housing I5 also has two 'pairs of transversely spaced, longitudinally extending, upstanding flanges 38 and 39 at its upper end.

The walls 26 and 21 ofthe well-like portion of the housing I5 Vhave bearing lbosses which are provided with aligned bores. A wheel shaft 45 is adapted to rotatefin anti-friction bearings 4I and 42 disposed in the bores of the respective walls 2S and 21 (Fig. 3). The shaft 4B has a reduced end 43 disposed in the bearing '42, with a shoulder of the shaft abutting theinner side of the bearing. A reduced portion 45 of the shaft 49 is located in the bearing 4I, a shoulder of the shaft abutting the inner side of this bearing. The end 46 of the wheel shaft 45 which projects forwardly from the bearing 4I is further reduced to receive Va Worm wheel 41 which is keyed thereto and held axially in place bya bolt 48 screwed into this end of the shaft. Mounted on the central portion of the shaft 49 within the-compartment 25 is a traction wheel 5B which preferably has a metal hub 5I anda resilient tire 512 adapt.- ed to engage against the lower surface of the flange I2 of the monorail -II In other instances, however, it Vmay be desirable to utilize a wheel made from other material and having nosep- The wheel 5U is connected for rota tion with the shaft 45 by a key 53 and held axially in place by a set screw 54. Whenthe wheel shaft 4B and the wheel 5f) are rotated by means to- 'be presently described, the wheel rolls along the monorail II, thus causing the tractor I to travel therealong'.

The wheel shaft mounting means, described above, can be readily installed in and disassembled from the housing I5 and for facilitating such assemblyand disassembly, the walls I5 and I1 of the housing are provided with openings 55 which are aligned with the wheel shaft 45, 'these openings being normally closed by cover vplates 56. To install the wheel 59 and its shaftV 45, which has progressively larger steps or portions of increased diameter from its left-hand end toward a midpoint `of the shaft, the following steps are carried out. The bearing 42 is rst pressed onto respective arms '65 and 5I the right-hand end 43 of the shaft 40. A sealing ring 42 is next slid over the left-hand end of the shaft 48 and into place against the left-hand end of the central enlarged portion 43' of the shaft, after which the ball bearing 4I is forced onto the shaft as shown in Fig. 3. A sub-assembly or shaft unit, comprising the shaft 4,\the bearings 4I and 42, and the sealing ring242, is thus formed.

Prior to inserting the shaft unit in the housing I5, the wheel 50 is lowered into the compartment 25. The shaft assembly, with its key 53 in place, is slid through the right-hand opening 55 and through the aligned holes in the walls 21 and 25 of the housing to .mount the wheel, the shaft sealing ring '42 being forced into place in the .bearinghole of the wall 25. A retainer ring 44' is next inserted through the left-hand opening 55 and slid onto the shaft 45 and secured against the boss of the wall 25 by screws. The retainer ring 51 is then secured againstthe boss of the wall 21, with shims (not shown) being employed to exert theproper force against the ball bearings to retain the shaft 40 axially in place.

The set vscrews 54 are nexttightened to fasten the wheel 59 to the shaft 40. Following this step, the worm wheel 41 is inserted throughthe lefthand opening 55 and keyed-to the left-,handend of the shaft 4i! as shown in-Fig.'3, the worm wheel being held in `place by the cap screw 48 and a ring 48. The cover plates 55xarenallysecured in place to close the openings 555.

Extending between the pairs of flanges 38 Land 39 are transverse pivot pins 58 and 59 to which are pivotally connected. At their outer free'ends, the four'arms G9 andl 5i carry respective wheels 62 and 63 which are adapted to engage and roll along the upper surface of the flange I2 of the monorail i.I,'the wheels beingrotatable on studsl and preferably, although not necessarily, flanged as shown. The arms 6U and 6I carry adjusting screws :55 and 6E which are screwed ther-cinto and which .have heads adapted to vengage opposite sides .of yvertical webs 61 extending between the pairs of flanges 38. and 39. By unscrewing the adjusting screws 55 and 56, they are forced against the webs 61 so as to pivot thearrns and 5E' rdownwardly. In this manner, .the four .wheels 6.2 and 63 are forced downwardly against the ange .I2 of the track or rail I I to support the tractor and the lower whee15 is, in eecndrawn upwardly against the lower side of .thetrack Il with :the resilient tire S52 compressing thereagainst :to effect maximurntraction- Due-to the positive engagement of the vwheels 52', 53 and 5G against the opposite sides of the track ange 2, `a highly efficient drive, free from slippage, .is eiected when the wheel 59 is rotated. Moreover, since the four wheels52, 53 are adjustable independently of `one another, by loweringor raising certain wheels, the tractor I9 may be readily leveled, bothlongitudinally and transversely.

The Worm wheel 41 is adapted to be rotated by a Worin 'I0 mounted on or formed integral with a countershaft 1I (Figs. 3 and 4) extending .beneath and normal to the wheelshaft 4.9. One end 'I2 of the shaft 'II is reduced in diameterand is received Within the-innerrace of a roller bearing 13 which is disposed within a recess l'I4 of the partition 20 of the housing I5. The other end of the shaft has a reduced portion 15 which is received` in the inner race of a. roller `bearing 16 which abuts a shoulder of the shaft and which is disposed within a bore 'T1 in the end wall I9.

A retainer ring 11 is fastened to the wall I9 and engages the roller bearing 16 to retain the worm shaft assembly in place with the worm meshing with the worm wheel 41. The shaft 'll projects outwardly from the wall i9 and carries a sprocket 18 by which the shaft is driven by means to be next described. It is to be noted that by the construction described above the countershaft 1| can be quickly installed in and removed from the housing |5 through the single bore 'El so that it is unnecessary to split the housing, that is, make the housing in separable parts for this purpose.

Referring now to Fig. 2, the power means for driving the traction wheel is located within l the lower portion of the housing i5. Attached to the forward side of the partition 20 by screws 19 is a cup-shaped mounting member 90 having a peripheral wall 8| and a rear wall 82 having a central hub portion 83 provided with an axial bore 84. The inner surface of the wall 9| preferably has recessed, axially, extending bosses 85 for receiving the stator 86 of an electric motor 81 which is forced into the mounting member 80. The rotor 88 of the electric motor is pressed onto the forward end of a rotor shaft 89. Forced onto a portion 90 of the shaft and disposed against a shoulder 9| thereof is the inner race of a ball bearing 92, the outer race of the bearing being received in an annular recess or counterbore 93 in the forward end of the hub portion 83 of the mounting member 80. A reduced portion 94 of the shaft 89 is disposed within the inner race of a ball bearing 95 having its outer race disposed in the bore 84. A snap ring 90 is seated in a peripheral groove of the shaft 89 and engages the rearward side of the ball bearing 95 to maintain the latter against a shoulder 97| of the shaft. A retainer ring 98 secured tc the forward face of the hub portion 93 by screws 99 retains the bearing 92 in the recess 93 so that axial movement of the shaft 89 is resisted.

The rotor shaft 89 is adapted to drive the worm shaft 1| through power transmission means to be next described. The power transmission means includes a iiuid coupling, indicated generally at |00 in Fig. 2. The driving element or runner |02 of the fluid coupling |00 is keyed to the rearward end |03 of the rotor shaft 89 and held against a shoulder |04 of the shaft by a ball bear- Y ing |05 which is forced against the runner by a nut |06 screwed onto the rearward end of the shaft. The driven element or runner |08 of the uid coupling is connected to a casing |09 which has a hub ||0 provided with a bore Ill. ADisposed in the bore is a sleeve ||2 which receives the ball bearing |05, previously described, the sleeve being secured to the casing |09 by bolts |3. A snap ring H3' is disposed in an annular groove within the sleeve ||2 and engages the face of the ball bearing |05. Also secured to the rearward end of the casing |09 by the bolts H3 is an end plate H4 which is secured one end of a drive shaft ||5. The shaft H5 carries a ball bearing H6 which is disposed in a bore Il in the end wall |9 of the housing i5. The shaft H5 projects rearwardly from the wall i9 to receive a sprocket ||8 which is secured thereto. The sprocket ||8 is adapted to drive the sprocket 18 by means of a chain ||9. t is within the concept of this invention, however, to employ other means, such as a train of gears, for transmitting power from the shaft ||5 to the shaft 1|. In any event, the cover 33 is applied to the end of 6 the housing |5 to enclose the driving means between the shafts |5 and 1|.

It will be apparent from the foregoing description and by observing Fig. 2 of the drawings that the elements of the power transmission means, including the mounting member 80, the motor 81, the shaft 89, the fluid coupling E00, the drive shaft ||5, and associated components, together provide a self-contained power unit which is adapted for convenient installation in and removal from the housing I5. It will also be observed that the power unit is insertable into the housing l5 through the open forward end thereof and that to mount the unit in the housing it is only necessary to guide the end of the drive shaft ||5 through the bearing ||6 and guide the rearward end of the mounting member 00 through the opening 2| in the partition 20 so as to position the flange of the member against the partition, after which the screws 19 are inserted and tightened to secure the unit in place. To remove the power unit from the housing, the reverse procedure is employed. It is important to note that by my improved construction in which the entire power unit is adapted for assembly outside the housing and is capable of being installed through an open end of the housing, it is unnecessary to provide a sectional housing having separable components requiring expert machining and fitting in order to obtain perfect alignment of the power transmission elements. It will also be apparent that by the present construction it is unnecessary to detachably connect the rotor 88 to the shaft 89 to permit assembly and disassembly of the parts, so

that the possibility of the rotor loosening on the shaft is entirely avoided. This is an improvement over other power units wherein it is necessary to secure the rotor to the shaft by set screws or similar means which are apt to loosen and cause displacement of the rotor and damage to the power unit. The present construction is, therefore, an important improvement over prior tractors in which the electric motor and iiuid coupling or clutch mechanisml are installed separately in opposite directions or merely mounted on a platform of the tractor.

y The power transmission means is assembled 4outside the housing I5 by first forcing the rotor onto the left-hand end of the shaft 89, then sliding the retainer ring 93 into place on the shaft adjacent the rearward side of the rotor, after Which the ball bearings 92 and 95 are pressed onto the shaft against the respective shoulders 9| and 91 and retained in place by split rings. The entire subassembly including the shaft 89, the rotor 88, the retainer ring 98 and the bearings 92 and 95, is inserted into the mounting member 80 through the open forward or left-hand end, as viewed in Fig. 2, the bearing 92 thus being disposed in the counterbore 93 while the bearing 95 is located in the bore 84. The screws 99 are then inserted and tightened to retain the subassembly in proper place.

The uid coupling is assembled on the rearward or right-hand end |03 of the shaft 89 by mounting the components |08, |09 and |02 thereon with the latter component disposed against the shoulder |04. The sleeve ||2, together with the ball bearing |05, is slid onto the end |03 of the shaft 89, the flanged end of the sleeve being disposed again-st the side of the element |09. By next screwing the nut |06 onto the threaded end of the shaft 89, the parts of the fluid coupling |00 are retained in place on the shaft. The ball asoman bearing II6 is'next .forced onto the-.driveshaft II and the flanged end I I4 of this-shaftiscconnected, along with the sleeve I I2, to'theuid coupling element I09 by means of'the bolts H3.

Thepower transmission unit including the motor Y8'I and fluid coupling H10, `carried-by .the mounting member 80, isiconvenientlyassembled outside the housing I5 and may'be readily installed within and removed from the housing. yTo install the transmission unit, it is merely inserted into the housing I5 through the forward vopen end `thereof, in other words, in a right-.handdirection as Aviewed `in`Fig. 2, -the mountingm'ember 80'being guided Vinto the opening 2| kof the partition v20 and the 'ball bearing IIB entering the bore III of the end wall I9 of thehousing. To retain the transmission unit in placeitlis only necessaryto apply vthe screws 'I9 so asto secure vthe 'peripheral flange of the mounting member 8U to -the partition. Following the-step vof securing the transmission unit in the housing I5, the driving sprocket I I3 and chain I I9 may be operatively connected to the drive shaft IIS, after which the cover members 33A and 3D mayfbe'applied -to the housing to cover the sprocekts II 8 and 'I8 and the chain H9, and to closethe forward end of the housing. It is to be noted at this point that when electric motors of different capacities are employed, mounting membersof different dimensions may be substituted for the one shown inthe-drawings, and when the moftor has a greater'longitudinal dimension, a cover member 30 of greater width will also be substituted.

Assuming that the -tractor I is in assembled condition and that it is mounted by the wheels 5I), 62 landIiS for movement along the monorail II, to effect travel of the tractor, the electric -motor 81, which isof the reversible type, is energized to cause rotation of its rotor shaft 89 which rotates in the bearings 92, 95 and |05. Rotary movement is thus communicated to the driving runner IGZ ofthe iluid coupling IUD and, through the medium of fluid interposed between the runner I`02 and the runner |08, the latter is also rotated. Due to the uid connection, slippage may occur between the `runners'at the start of rotation to avoid sudden starting ofthe tractor but as the drive continues slippage is reduced-so that eventually the drivenrunner IfIl8 and the drive shaft II5 are rotated at a speed which is only slightly less than that of the `shaft 89.

The countershaft II is ydrivenfrom the shaft 'H55 by means of the chain I i9 and, through the 'medium of the worm 10 andworm 'wheel vll'l'the wheel shaft vlll and its traction wheel 50 are rotated, the direction Aof rotation o-f the wheel being in accordance with the directionof rotation Aof the rotor 88 of the reversible electric 'motor8'1.

Means are embodied within thehousing I5 for controlling the operation of the electric motor 81. Referring to Figs. 2 and 6, the control means includes a reversing starter I 25 and a transformer [25 mounted on the partition 20 in the space located Aabo-ve the mounting 'member 80 so as to .be readily accessible by merely remov- .ing the cover .30. Electric current for operating .the motor 81 maybe derived through a line :|121

*,(Fig. l) which may lead to anysource of elecmotor. By this -arrangement;the tpush button control I28 can operate from a relativelyrlow v.) pilot ycircuit regardless of vthe -fvoltage used for .the motor (usually2'20 or-440v.). :Leads are brought to a terminal block |29 so that during installation .it is simply'necessary to `join the control wires to the appropriately marked terminals of the blockand the powerlines Ato their respective terminals to complete thevassembly of the motor control means.

It will be apparent to lone skilled inthefart that various modifications might be madeinzthe construction of the tractor which would fall with--V in the spirit of thisinvention. Consequently, I do'not wish to be limited in this respect, butfdesire to be afforded the full scope of the-appended claims.

I claim as my invention:

1. A tractor adapted for :movement along track, comprising: a one-piecehousing having ta bottom wall, side walls, an end wall, a .vertical partition in said housing :provided with-'anopening, and lan'open end; wheelfmeans carried Vby said housing yand engaging opposite sides ofthe track to adapt said housing to travel therealong; and a power transmission means within said housing for driving' at least one of vsaid-.wheel means, said transmission :means Vincluding a driving element, a fluid-actuated'couplingIfor-'operating said element,an electric motor :fornactuating said coupling, said coupling :having 4a drive shaft rotatable in Vsaid Yend Wall, and :a mounting member detachably -secured to said partition within said vopening thereofand -supporting said motor, the portions of said transmission .means :between said partition and Vend wall being of less transverse .dimensions 'thanfsaid opening whereby said transmissionis insertable as a unit into said housing vthrough'said 7open end thereof.

2. A tractor adapted for movement lalong a track, comprising a 'one-piece 'housing havinga bottom wall, sidewalls, an end fwall, `a vertical partition in said housing provided withan opening, and an open end; -wheelmeans carriedxby said housing andengagingvopposite 'sides of the track-to adapt said housingto travel therealong; and a power transmission means Within said housing for driving at least one vof said wheel means, said transmission means includirrgaidriv- .ingelement a fluid-actuated coupling vfor operating said element, an'r electric motor :having a rotor shaft .for actuating-said coupling, said coupling having a drive shaft rotatable in said end wall, and `a mounting member Ydetachably vsie-- cured to said partition `within.'said'openingithereof and supporting said motor, said mounting .member having a bearing in which said rotor shaft is rotatable, the portions of said transmission means between said partition -and end wall being of less transverse dimensions than said opening whereby said transmission-is yinsertable as a unit into said housing throughsaid open vend thereof.

3. A `tractor as d'ened in claim l .in which -saidvuid-actuated coupling includes a first 4memvrotor Vshaft :and said second member being carried by said drive shaft,saidvsecond member having an axial bearing in which an end of vsaid .rotor shaft is rotatable.

4. A tractor adapted for movement along Ya track, comprising: .a one-piece housing having 9 a bottom wall, side walls, an end wall, a vertical partition in said housing provided with an opening, and an open end; a bearing in said end wall; a fluid-actuated coupling disposed-within said housing and including a rst rotatable member and a second rotatable member adapted to be driven from said first member by fluid disposed therebetween, said second member having an axial drive shaft rotatable in said bearing and projecting from said end wall; wheel means rotatable on said housing and engageable with the track to adapt said housing to travel therealong; driving means operated by said drive shaft and operative to rotate said wheel means; a hollow mounting member detachably secured to said partition within said opening and having a bearing; and an electric motor having a stator supported within said mounting member and a rotor rotatable within said stator, said rotor having a shaft rotatable in said bearing of said mounting member in axial alignment with said drive shaft, said rotor shaft carrying said first member, and said mounting member, the portions of said motor and said fluid clutch between said partition and end lwall being of less transverse dimensions than said opening whereby said transmission is insertable as a unit into said housing.

5. A tractor as defined in claim 4 in which said second rotatable member has an axial bore, and including: an annular element removably secured within said bore; and an anti-friction bearing disposed within said annular element in which an end of said rotor shaft is rotatable.

6. A tractor as defined in claim 4 and includ- Cil 10 ing: a cover member detachably secured to said housing and closing said open end thereof; and a cover member detachably secured to said end wall and enclosing said driving means.

7. A tractor as dened in claim 4 in which said driving means includes: a driven shaft rotatable on said' housing and provided with a worm; power transmission means between said drive shaft and said driven shaft by which said driven shaft is rotated b-y said drive shaft; a @wheel shaft carrying said wheel means; and a worm Wheel on said wheel shaft in mesh with said worm.

AMBROSE MAZZOLA.

References Cited in the ille of this patent UNITED STATES PATENTS Number Name Date 870,607 Amberg Nov. 12, 1907 1,199,359 Fottinger Sept. 26, 1916 2,038,732 Guthrie Apr. 28, 1936 2,162,688 Lawrence June 13, 1939 2,228,034 Nelles Jan. 7, 1941 2,322,785 Knox June 29, 1943 FOREIGN PATENTS Number Country Date 106,443 Germany Oct. 15, 1898 OTHER REFERENCES An article which appeared in the December 1941 issue of the Mining Congress Journal" pages 30-34. A copy may be found in the Scientie Library of the Patent Office. 

